Embodiments disclosed herein relate to a fuel system, and more specifically, to a fuel system including one or more adjustable sump pads for use in an aircraft.
Aircraft, such as airplanes, helicopters, turbo props and tilt rotor aircraft typically often include one or more containers for storage of fuel on board the aircraft. Each container provides a sealed volume for the storage of fuel and may vary from a discrete tank, such as having one or more bladders, to nothing more than a sealed chamber m the aircraft structure. The containers include fittings and/or connections for filling the container with fuel, outputting the fuel to an aircraft engine, and may also include ancillary components such as fuel pumps, fuel filters, vent fittings, and sump pads.
Typically, in an aircraft such as a helicopter, the containers are located within the fuselage or are mounted in a space external to the fuselage, such as within the sponsons or protrusions from the fuselage of the aircraft. The external location allows for easy access for installation and mounting of the fuel containers into the sponsons. In addition, the sponsons may provide extra fuel capacity or allow for more free space within the fuselage.
Due to the wide range of pitch angles or attitudes that a helicopter may experience in flight and the desire to minimize unusable fuel, sump pads are often positioned within the fuel tank to funnel fuel toward the fuel supply inlet. Inclusion of sump pads is intended to optimize the use of the fuel within the tank. However, sump pads are typically large and add weight to the aircraft while reducing the usable fuel volume of the fuel tank. In addition, when an adequate amount of fuel is within the tanks, the sump pads provide no benefit. Additionally, there is typically a significant amount of unusable fuel that the sump pads are unable to mitigate.